Hou Tian-Ya, Mao Xiao-Fei, Zhang Rui-Ke
Faculty of Psychology, Naval Medical University, Shanghai 200433, China.
World J Psychiatry. 2025 Sep 19;15(9):107754. doi: 10.5498/wjp.v15.i9.107754.
Working memory serves as a fundamental cognitive function that substantially impacts performance in various cognitive tasks. Extensive neurophysiological research has established that theta oscillations (4-8 Hz) play an essential role in supporting working memory operations. Theta-band transcranial alternating current stimulation (tACS) offers a potential mechanism for working memory enhancement through direct modulation of these fundamental neural oscillations. Nevertheless, current empirical evidence shows substantial variability in the observed effects of theta-tACS across studies.
To conduct a systematic review and meta-analysis evaluating the effects of theta-tACS on working memory performance in healthy adults.
A systematic literature search was performed on PubMed, EMBASE, and Web of Science up to March 10, 2025. Effect sizes were computed using Hedges' with 95% confidence intervals (CIs), with separate meta-analyses for all included studies and for distinct working memory paradigms [n-back and delayed match-to-sample (DMTS) tasks] to examine potential task-specific effects. Subgroup analyses and meta-regression were performed to evaluate the influence of key moderating variables.
The systematic review included 21 studies (67 effect sizes). Initial meta-analysis showed theta-tACS moderately improved working memory (Hedges' = 0.405, 95%CI: 0.212-0.598). However, this effect became nonsignificant after correcting for publication bias (trim-and-fill adjusted Hedges' = 0.082, 95%CI: -0.052 to 0.217). Task-specific analyses revealed significant benefits in n-back tasks (Hedges' = 0.463, 95%CI: 0.193-0.733) but not in DMTS tasks (Hedges' = 0.257, 95%CI: -0.186 to 0.553). Moderator analyses showed that performance in n-back tasks was influenced by stimulation frequency ( = 0.001), concurrent status ( = 0.014), task modality ( = 0.005), and duration ( = 0.013), whereas only the region of targeted stimulation ( = 0.012) moderated DMTS tasks.
Theta-tACS enhances working memory in healthy adults, with effects modulated by the task type and protocol parameters, offering dual implications for cognitive enhancement and clinical interventions.
工作记忆是一种基本的认知功能，对各种认知任务的表现有重大影响。广泛的神经生理学研究表明，θ振荡（4 - 8赫兹）在支持工作记忆操作中起着至关重要的作用。θ波段经颅交流电刺激（tACS）通过直接调节这些基本神经振荡，为增强工作记忆提供了一种潜在机制。然而，目前的实证证据表明，不同研究中观察到的θ - tACS效应存在很大差异。
进行一项系统评价和荟萃分析，评估θ - tACS对健康成年人工作记忆表现的影响。
截至2025年3月10日，在PubMed、EMBASE和Web of Science上进行了系统的文献检索。使用Hedges' d计算效应量，并给出95%置信区间（CIs），对所有纳入研究以及不同的工作记忆范式（n - 回溯和延迟匹配样本（DMTS）任务）分别进行荟萃分析，以检验潜在的任务特异性效应。进行亚组分析和荟萃回归以评估关键调节变量的影响。
系统评价纳入了21项研究（67个效应量）。初始荟萃分析表明，θ - tACS适度改善了工作记忆（Hedges' d = 0.405，95%CI：0.212 - 0.598）。然而，在校正发表偏倚后，这种效应变得不显著（修剪填充调整后的Hedges' d = 0.082，95%CI： - 0.052至0.217）。任务特异性分析显示，n - 回溯任务有显著益处（Hedges' d = 0.463，95%CI：0.193 - 0.733），但DMTS任务没有（Hedges' d = 0.257，95%CI： - 0.186至0.553）。调节因素分析表明，n - 回溯任务的表现受刺激频率（p = 0.001）、并发状态（p = 0.014）、任务模态（p = 0.005）和持续时间（p = 0.013）影响，而DMTS任务仅受靶向刺激区域（p = 0.012）调节。
θ - tACS可增强健康成年人的工作记忆，其效应受任务类型和方案参数调节，对认知增强和临床干预具有双重意义。
